1. Field of the Invention
Various embodiments of the invention are directed to filling of portable therapeutic gas cylinders. More particularly, various embodiments of the invention are directed to determining, by a cylinder fill device, the rated pressure of a therapeutic gas cylinder.
2. Background
Patients with respiratory difficulties that are required to breathe enriched oxygen may be ambulatory by using a portable oxygen cylinders. Portable oxygen cylinders may range in size from cylinders that require a two-wheel dolly to be moved around, to those cylinders that fit neatly within a carrying case the size of a large purse, and also may be worn in a fashion similar to a back pack.
One of the factors that determines how long a portable cylinder can supply oxygen to a patient is the volume of the cylinder. The larger the volume, the larger the size of the cylinder. Another factor that determines how long a portable cylinder can supply oxygen to a patient is the pressure that the portable cylinder can withstand. If the patient has a choice between two portable cylinders having the same volume, yet one portable cylinder may be filled to a pressure of 3,000 pounds per square inch (psi), and a second portable cylinder can be filled only to 2,000 psi, the higher pressure cylinder in this case (and assuming the same volumes) holds more oxygen.
Some patients that utilize portable cylinders gas have within their homes devices that can fill or refill the portable cylinders. While home-based devices may be capable of filling cylinders with differing fill pressures, discerning the rated pressure of an attached cylinder by a home-based system is difficult.